Nickel phosphate-promoted supported nickel catalyst



United States Patent 3,538,019 NICKEL PHOSPHATE-PROMOTED SUPPORTEDNICKEL CATALYST Robert J. Capik and Leon W. Wright, Wilmington, Del.,

assignors to Atlas Chemical Industries, Inc., Wilmington, DeL, acorporation of Delaware No Drawing. Filed Mar. 7, 1968, Ser. No. 711,212Int. Cl. B01j 11/74 US. Cl. 252-437 Claims ABSTRACT OF THE DISCLOSURECatalysts which comprise finely divided metallic nickel and finelydivided nickel phosphate supported on an inert carrier wherein the totalnickel is from 12 to 45% by Weight, based on total weight of catalyst,the phosphate (P0 content is from 0.6% to 23% by weight, based on thetotal Weight of catalyst, and the ratio of total nickel to phosphorus isgreater than 2.84. The catalysts are useful for the production ofpolyhydric alcohols from carbohydrates.

This invention relates to improved catalysts and to methods for theproduction of such catalysts. This invention further relates to animproved process for the production of polyhydric alcohols fromcarbohydrates. More particularly, this invention relates to nickelphosphate promoted supported nickel catalysts which are useful for theproduction of polyhydric alcohols by the simultaneous hydrolysis andhydrogenation of carbohydrates.

The term carbohydrates as used throughout the specification and appendedclaims includes monosaccharides and polysaccharides.

The term polysaccharide as used throughout the specification andappended claims includes those saccharides containing more than onemonosaccharide unit.

A wide variety of catalysts have been proposed for the hydrogenation ofmonosaccharides, such as glucose and fructose, to polyhydric alcohols.The catalysts most often used for this purpose are the Raney nickelcatalysts, such as those described in J.A.C.S., 54, pages 4116-4117,(1932) and US. Pat. No. 2,983,734, and finely divided supported nickelcatalysts, such as those disclosed in US. Pat. No. 2,749,371. Thesehydrogenation catalysts, however, have not been entirely satisfactory asthey exhibit low activity and low surface area and produce low yields ofthe desired polyhydric alcohol. Furthermore, the finely dividedsupported nickel catalysts are deactivated during a single usage in atypical hydrogenation reaction. Another serious disadvantage of thesecatalysts is that they are not effective for the preparation ofpolyhydric alcohols directly from polysaccharides. Various catalystshave been proposed for the simultaneous hydrolysis and hydrogenation ofpolysaccharides to polyhydric alcohols. Examples of these catalysts aredisclosed in US.

Pat. No. 2,518,235. These catalysts also suflfer from the disadvantagethat they exhibit low activity and are deactivated during a single usagein a typical hydrogenation reaction. Accordingly, there is a great needin the art for a catalyst which would be used for the production ofpolyhydric alcohols from monosaccharides and polysaccharides and whichwould overcome the aforementioned disadvantages.

It is an object of this invention to provide a novel catalyst. It isanother object of this invention to provide a catalyst which wouldovercome the aforementioned disadvantages of the prior art catalysts. Itis another object of this invention to provide a catalyst for theproduction of polyhydric alcohols from carbohydrates. It is anotherobject of this invention to provide a catalyst for the simul 3,538,019Patented Nov. 3, 1970 taneous hydrolysis and hydrogenation ofcarbohydrates to polyhydric alcohols. It is a further object of thisinvention to provide a catalyst having high activity. It is anotherobject of this invention to provide a catalyst having an increasedsurface area. It is another object of this invention to provide acatalyst which has increased stability, thereby allowing reuse of thecatalyst without reactivation. It is another object of this invention toprovide a catalyst which is highly effective for the production ofpolyhydric alcohols directly from polysaccharides. It is another objectof this invention to provide a catalyst which gives high yields of thedesired polyhydric alcohols. It is a further object of this invention toprovide a process for the production of such catalyst. It is a furtherobject of this invention to provide an improved process for thepreparation of polyhydric alcohols from carbohydrates.

The foregoing objects and still further objects are accomplishedaccording to the present invention by providing catalysts which comprisefinely divided metallic nickel 'and finely divided nickel phosphatesupported on an inert carrier wherein the amounts of metallic nickel,nickel phosphate, and inert carrier present in the catalyst are suchthat the total nickel content, that is metallic nickel plus combinednickel, is from 12% to 45% by weight, based on the total weight ofcatalyst, the phosphate (P0 content is from 0.6% to 23% by Weight, basedon the total weight of catalyst, and the weight ratio of total nickel tophosphorus is greater than 2.84. In order to achieve the objects andadvantages of this invention it is essential that the catalysts containamounts of metallic nickel, nickel phosphate and carrier to furnish atotal nickel content, a phosphate (P0 content, and a ratio of totalnickel to phosphorus within the ranges defined above.

The inert carrier on which the finely divided metallic nickel and finelydivided nickel phosphate are deposited may be any of the inert materialsused heretofore for supporting hydrogenation catalysts. Illustrativeexamples of such inert carriers or supports are diatomaceous earth,finely divided silica, kieselguhr, and activated carbon. The preferredcarriers are diatomaecous earth and activated carbon.

The catalysts of this invention may also contain small amounts of finelydivided iron supported on the inert carrier. It has been found thatsmall amounts of iron increase the activity of the catalyst. The amountof iron present in the catalyst may be up to 2.5%, preferably 0.1% to2.0%, by weight, based on the total weight of catalyst. The activity ofthe catalyst may be even further increased by the presence of up to 2.0%by weight, based on the total weight of catalyst, of finely dividedchromium, cerium, and copper.

The preferred catalysts of this invention comprise finely dividedmetallic nickel, iron, and nickel phosphate supported on an inertcarrier wherein the total nickel content is from 15% to 30% by weight,based on the total Weight of catalyst, the phosphate (P0 content is from1% to 14% by weight, based on the total weight, of catalyst, the ironcontent is from 0.1% to 2.0% by weight, based on the total weight ofcatalyst, and the weight ratio of total nickel to phosphorus is greaterthan 3.28.

The catalysts of this invention have an activity from two to four timesas high as the activity of a supported nickel catalyst which contains nonickel phosphate. In order to illustrate the increased activity of thecatalysts of this invention, catalysts containing various amounts ofnickel phosphate were used in the hydrogenation of glucose inessentially neutral, 50 percent by weight aqueous solution at C. andunder a hydrogen pressure of 1500 psi, with sufficient catalyst tofurnish 1.0%

by weight of total nickel based on the weight of glucose. As thehydrogenation of glucose is a pseudo first order reaction, the activityor rate constant is given by the well-known first-order reactionequation:

o =kt V In wherein k is the reaction rate constant, C is the initialsugar concentration, and C is the sugar concentration after elapsed timet. The results are shown in Table I.

TABLE I Weight percent k hours- (recipro- Catalyst No. (P04) cal hours)0. 0 3. 9 0. 6 9. 2 0. 8 9. 4 1. 4 10. 4 2. 0 10. 6 5. 8 10. 4 7. 6 17.3 13. 0 l8. 7 l5. 3 l5. 2

The catalysts of this invention are highly resistant to deactivation,thereby allowing reuse of the catalyst with out reactivation. It has nowbeen found that the catalysts of this invention may be used in six toeight consecutive hydrogenation runs before recativation is required.Supported nickel catalysts known prior to this invention, that issupported nickel catalysts which do not contain nickel phosphate,require reactivation after only one hydrogenation run. In order toillustrate the increased stability of the catalysts of this invention ascompared to phosphate free supported nickel catalysts, glucose washydrogenated at 140- C. with a phosphate free supported nickel catalystand with a catalyst of this invention which has a phosphate (PO 9content of 2.0% by weight. The phosphate free catalyst had an initialactivity of 3.9 reciprocal hours and an activity of 0.7 reciprocal hourafter only one hydrogenation run. The phosphate containing catalyst hadan initial activity of 10.6 reciprocal hours, an activity of 8.3reciprocal hours after three runs, and an activity of 5.8 reciprocalhours after five runs.

The catalysts of this invention may be prepared by forming a slurry ofan inert carrier in an acidic, aqueous solution of nickel nitrate andnickel phosphate, neutraliziing the slurry with an alkali metalcarbonate to precipitate nickel carbonate, nickel hydroxide, and nickelphosphate on the inert carrier, and reducing the nickel carbonate andnickel hydroxide to metallic nickel. The aqueous solution of nickelnitrate and nickel phosphate may be prepared by adding phosphoric acidto an aqueous solution of nickel nitrate or by treating metallic nickelwith nitric acid to form nickel nitrate and then adding phosphoric acid.Catalysts containing finely divided metallic iron, copper, chromium, orcerium are prepared by adding the nitrate of the metal to the aqueoussolution of nickel nitrate and nickel phosphate prior to the addition ofthe alkali metal carbonate. A preferred method of preparing thecatalysts of this invention comprises: forming a slurry of inert carrierin an acidic, aqueous solution of nickel nitrate and nickel phosphate;heating the slurry to 75 to 100 0.; adding alkali metal carbonate to theheated slurry to precipitate nickel carbonate, nickel hydroxide, andnickel phosphate onto the surface of the inert carrier, the nickelcarbonate converting to nickel hydroxide due to the elevatedtemperature; and heating the catalyst to a temperature from 450 C. to550 C. in the presence of hydrogen to reduce the nickel hydroxide tometallic nickel. The catalysts may also be prepared in situ by addingnickel phosphate to a feed solution containing the carbohydrate to behydrogenated and a supported nickel catalyst which does not contain anyphosphate.

It has now been discovered that the hydrogenation of monosaccharide andthe simultaneous hydrolysis and hydrogenation of polysaccharides may beconducted in a practical and economical manner, substantially free ofdegradation and transformation reactions, and with an almostsubstantially complete conversion of the monosaccharide andpolysaccharide to polyhydric alcohol, by the novel method ofincorporating a catalyst of this invention into an aqueous solution ofcarbohydrate and subjecting the mixture to the action of hydrogen underpressure at an elevated temperature.

The process of this invention may be broadly described as a method forthe preparation of polyhydric alcohols from carbohydrate which comprisesadding a small amount of a catalyst of this invention to an aqueoussolution or suspension of the carbohydrate and treating the resultingmixture with hydrogen under a pressure of about 25 to about 200atmospheres and a temperature between about 120 C. and about 210 C.until the hydrolysis and hydrogenation reaction has been effected to thedesired extent. During the reaction, any polysaccharide is hydrolyzed toits basic monosaccharide whose aldehyde or ketone groups are thenhydrogenated to hydroxyl groups to produce the desired polyhydricalcohol of the monosaccharide. Those polysaccharides having freealdehyde or ketone groups in their molecular structure before they aresubjected to the process of this invention may have these groupshydrogenated at the same time as the molecule is hydrolyzed. At anyrate, both hydrolysis and hydrogenation reactions appear to be takingplace simultaneously when polysaccharides are subject to the process ofthe invention, and the reaction results in the desired polyhydricalcohols of the basic structural monosaccharides. Polysaccharidescomposed of different monosaccharides are hydrolyzed and hydrogenated tothe polyhydric alcohol of the respective monosaccharides.Monosaccharides containing an aldehyde group are hydrogenated alsoexclusively by the process of this invention to a polyhydric alcoholcontaining the same number of carbon atoms, the same space configurationof units attached to the carbon atoms, and with a hydroxyl groupattached to the aldehyde carbon atom in place of the oxygen atom.Glucose, for example, is hydrogenated almost exclusively to sorbitol.Monosaccharides containing a keto group in the molecule are hydrogenatedto a mixture of approximately equal amounts of two different polyhydricalcohols due to the symmetric nature of the keto carbon atom. Bothresulting polyhydric alcohols contain the same number of carbon atoms asthe monosaccharide with the same space configuration of units attachedto the carbon atoms, but one of the polyhydric alcohols has a hydroxylgroup on one side of the keto carbon atom in place of the oxygen atom,and the other polyhydric alcohol has the hydroxyl group on the oppositeside of the keto carbon atom in place of the oxygen atom. Fructose, forexample, has a keto group at the second carbon atom and the molecule ishydrogenated to approximately equal amounts of sorbitol and mannitol.

Illustrative examples of carbohydrates which may be converted topolyhydric alcohols in accordance with the process of this inventioninclude, for example, glucose, fructose, galactose, mannose, altrose,allose, idose, gulose, arabinose, talose, ribose, xylose, sucrose,maltose, lactose, cellobiose, melibiose, invert sugar, starch, andstarch decomposition products such as dextrin, glucose syrups, and cornstarch hydrolyzates. Mixtures of carbohydrates may also be used in theprocess of this invention. For example, a mixture of sucrose and starchmay be subjected to the simultaneous hydrolysis and hydrogenationprocess, or a mixture of glucose and dextrin may be used.

The carbohydrate or carbohydrates to be subjected to the process of thisinvention are dissolved in water at the appropriate concentration forthe hydrolysis or hydrogenation reaction. Concentrations ofcarbohydrates from 20% to about by weight are usually employed for thereaction. Carbohydrate concentrations in the range of 40% to 70% byweight react particularly smoothly in the reaction and suchconcentrations are, therefore, the more preferred for this invention. Itis not entirely necessary for the carbohydrates to form true solutionswith the water as suspensions, and colloidal solutions of carbo hydratesreadily react.

The amount of catalyst to be used in the process of this invention mayvary over a wide range and will depend upon the particular catalyst,carbohydrate, temperature, and pressure which are employed in theprocess. In general, the higher the level of phosphate in the catalystand the higher the temperature and pressure used, the less catalyst isrequired. Polysaccharides tend to require a higher level of catalystthan the monosaccharides. Catalyst concentrations from about 0.3% toabout 5.0%, preferably from about 0.6% to about 1.5%, by weight of totalnickel based on the weight of carbohydrate are suitable.

The pressures and temperatures employed in the process of this inventionmay vary over Wide limits. Because of the higher reaction rate found inthe hydrogenation systems of the present invention, the reaction may becarried out at temperatures from about 120 C. to about 210 C. andhydrogen pressures from about 25 atmospheres to about 200 atmospheres.The preferred ranges of pressure and temperature are from about 75atmospheres to about 15 atmospheres and from about 150 C. to about 200C. It is to be understood, however, that higher and lower pressures andtemperatures than those described above may be used when deemednecessary or desirable.

The time of reaction will depend upon the specific carbohydrate orcarbohydrates being acted upon, the specific hydrogenation catalystsused, pressure, temperature, and the concentration of the carbohydrate.Generally, the time may be about 30 to about 150 minutes. However, somereactions may take longer or shorter periods of time; and, in any event,the reaction should be continued until the hydrolysis and hydrogenationhas been completed.

The reactants may be added to the reaction chamber in any suitablemanner or in any suitable order. It is preferred to add the catalyst tothe aqueous solution or suspension of the carbohydrate and then add thehydrogen under pressure and commence heating the mixture to the desiredtemperature.

The reaction is carried out in any suitable type of apparatus whichenables intimate contact of the reactants and control of the operatingconditions and which is resistant to higher pressures involved. Theprocess may be carried out in batch, semi-continuous, or continuousoperation.

Upon completion of the reaction, the catalyst is removed by filtrationor decantation and the polyhydric alcohol may be separated from thefiltrate by any suitable means, such as, filtration, washing,crystallization, solvent extraction, and evaporation.

In order that those skilled in the art may better understand how thepresent invention may be practiced, the following examples are given.These examples are set forth solely for the purpose of illustration andany specific enumeration of details contained therein should not beinterpreted as expressing limitations with this invention. All parts andpercentages are by weight unless otherwise stated.

EXAMPLE 1 98.15 grams of nickel nitrate-6H O and.8.69 grams of ironnitrate'9H O are dissolved in about 300 ml. of distilled water. 29.2grams of -85 phosphoric acid and 72.0 grams of kieselguhr are added tothe solution. The resulting slurry is then heated, with stirring, to 85to 95 C. and 53.6 grams of anhydrous sodium carbonate in 150 ml. ofdistilled water are added over a one hour period, the pH of this slurryrising to 7.9 during the addition of the sodium carbonate solution. Theslurry is maintained at 90 C. for an additional 45 minutes and thenfiltered and washed with distilled water. The wet catalyst is then driedat 150 C. for 17 hours. The dried green catalyst is ground to passthrough a 325 mesh screen and then activated by passing a stream ofhydrogen over it at 500 C. for 30 minutes. The catalyst assay, asdetermined by laboratory analysis, was 2% iron, 6.4% metallic nickel,26.7% nickel phosphate, the remainder being inert carrier. The greencatalyst has a surface area of 194 m. /g. (BET) and a pore volume of0.39 ml./g.

EXAMPLE 2 200 grams of nickel nitrate-6111 0 and 17.5 grams of ironnitrate-9H O are dissolved in 600 ml. of distilled water. 24.7 grams ofan solution of phosphoric acid and 147 grams of activated carbon arethen added. The resulting slurry is heated, with stirring, to 85 to C.and 109 grams of anhydrous sodium carbonate in 300 ml. of water addedover a one hour period. The slurry is then maintained at 90 C. for anadditional 45 minutes, filtered, and washed with distilled Water. Thecatalyst is then dried at 5 inches of merculy absolute pressure for 20hours at C., ground, and activated by passing a stream of hydrogen overit at 500 C. for 30 minutes. The catalyst contains 10.3% metallicnickel, 1.1% iron, and 18.6% nickel phosphate, the remainder being thecarbon carrier.

EXAMPLE 3 19.5 liters of demineralized water, 217 grams metallic iron,and 4340 grams of metallic nickel are added to an agitated vessel fittedwith a cooling jacket. While cooling this slurry, 18 kilograms of 70%nitric acid is slowly added. The contents of the vessel are then allowedto slowly heat up to to 200 F. The contents of the vessel are held atthis temperature for 3 hours, thereby converting the metals to thecorresponding nitrate. To the resulting solution, 15 liters ofdemineralized water, 12.35 kilograms of kieselguhr and 1.54 kilograms of85% phosphoric acid are added. The resulting slurry is heated withstirring to 90 C. 7700 grams of anhydrous sodium carbonate dissolved in31 liters of distilled water are then added over a period of two hours.The resulting slurry is then held for one hour at 90 C., the pH risingto 7.2. The slurry is then filtered hot on a plate and frame filterpress, and the filter calke washed with 250 liters of the demineralizedwater. The filter cake is partially dried by blowing it with hot air andtransferred to a vacuum oven Where the moisture content is reduced to1-4% by drying for 16 to '20 hours at 105 C. and about 4 to 7 inches ofmercury absolute pressure. The catalyst is then activated by contactingit, in a continuous rotary kiln, with acounter current flow of hydrogenat a temperature of about 500 C. The activated catalyst is then storedin the absence of oxygen until used. Analysis of the activated catalystis 16.2% metallic nickel, 1.1% iron, and 12.5% nickel phosphate.

EXAMPLE 4 73 grams of metallic iron, 1,410 grams of metallic nickel, and6.3 liters of demineralized water are placed in a stirred, cooled vesseland 5.86 kilograms of 70% nitric acid are added slowly. After thetemperature has been stabilized at 90 C., 20 more liters ofdemineralized water are added. 3.7 kilograms of kieselguhr, 13.1kilograms of a dried spent catalyst and 1.54 kilograms of 85 phosphoricacid are added. The slurry is then maintained at 90 C. for 15 to 30minutes. 10 kilograms of sodium carbonate and 4 0 kilograms ofdemineralized water are added over a period of about 2 hours whilemaintaining the temperature at 90 C. The slurry is then held anadditional hour at 90 C. and then filtered hot in a plate and framefilter press. The filter cake is then washed and dried and activatedwith hydrogen in accordance with the process described in Example 3. Theactivated catalyst had the following analysis: 16.3% metallic nickel,1.1% iron, and 12.5% nickel phosphate.

7 EXAMPLE 88 grams of nickel nitrate-6H O and 3 grams of 85% phosphoricacid are added to a slurry of 53 grams of kieselguhr in 116 grams ofwater. The resulting slurry is heated, with stirring, to 85 to 95 C. and38 grams of anhydrous sodium carbonate in 1510 grams of distilled waterare added over a one hour period, the pH of the slurry rising to 7.2.The slurry is maintained at 90 C. for an additional 45 minutes and thenfiltered and washed with distilled water. The Wet catalyst is then driedat 150 C. for 17 hours. The dried green catalyst is ground to passthrough a 325 mesh screen and then activated by passing a stream ofhydrogen over it at 500 C. for one hour. The catalyst assay, asdetermined by laboratory analysis, was 19.8% metallic nickel and 7.2%nickel phosphate, the remainder being inert carrier.

EXAMPLE 6 200 grams of nickel nitrate-6H. O, 8 grams of coppernitrate-311. 0, and 9 grams of iron nitrate-9H O are dissolved in 600ml. of distilled water. 30 grams of an 85% solution of phosphoric acidand 150 grams of kieselguhr are added. The resulting slurry is heated,with stirring, to 85 to 95 C. and 110 grams of anhydrous sodiumcarbonate in 300 m1. of water added over a one hour period. The slurryis maintained at 90 C. for an additional 45 minutes and then filtered.The filter cake is washed with distilled water, dried at 5 inches ofmercury absolute pressure for hours at 105 C., ground, and activated bypassing a stream of hydrogen over it at 500 C. for minutes. Theresulting catalyst contains 8.1% metallic nickel, 0.55% iron, 0.78%copper, 21.8% nickel phosphate, and 68.77% kieselguhr.

EXAMPLE 7 11.55 grams of the catalyst of Example 1 are added to 200grams of a 50% aqueous solution of corn starch hydrolyzate under in aninert nitrogen atmosphere. The corn starch hydrolyzate used is ahydrolysis product of corn starch and contains about 63% dextrose, about17% disaccharides, about 4% trisaccharides, about 3% tetrasaccharides,and about 12% higher polysacharides. The resulting slurry has a pH of6.5. The slurry is then added to a stirred stainless steel autoclave andheated in the presence of hydrogen to 160 C., while maintaining thehydrogen pressure at 1500 p.s.i.g. The reaction is continued at thistemperature for 30 minutes. The temperature is then increased to 180 C.and the pressure to 2000 p.s.i.g. and the reaction continued for anadditional 30 minutes. The reaction product, which has a pH of 3.1, isthen cooled and filtered. The filtrate is passed through a bed of an ionexchange resin and concentrated to 70% solids. The analysis of thisproduct on a dry basis was 94.3% sorbitol.

EXAMPLE 8 Example 7 is repeated except that 8.6 grams of catalyst areused. The initial pH of the slurry is 6.4 and after reaction the pH is3.4. The sorbitol assay (percent of solids) is 96.9%.

EXAMPLE 9 Example 7 is repeated except that 5.8 grams of catalyst areused. The initial pH is 6.3 and the final pH is 4.3. The assay of thisproduct is 95.8% sorbitol.

EXAMPLE 10' 200 pounds of a 50% aqueous solution of corn starchhydrolyzate having a dextrose equivalent of 77.5 are slurried with 8.9pounds of a catalyst consisting of finely divided metallic nickel andfinely divided nickel phosphate supported on kieselguhr wherein thetotal nickel content is 22.5% by weight of catalyst and the P0 contentis 2.0% by weight of catalyst. Successivebatches of this slurry are thenpumped at a rateof 51 pounds per hour to a system of five autoclavesconnected in series. To

the second autoclave phosphoric acid is added at a rate of 004 pound perpound of sugar. The pressure on all five autoclaves was maintained at2000 p.s.i.g. of hydrogen and the slurry agitated by the addition ofhigh pressure hydrogen. The temperature in the first autoclave ismaintained at C., C. in the second reactor and C. in each of theremaining three reactors. The product of the fifth reactor is filteredand ion exchanged, and was found to contain 92% sorbitol, based on theweight of total solids.

EXAMPLE 1 l 1.5 grams of nickel phosphate and 10 grams of a standardnickel catalyst consisting of finely divided metalic nickel and finelydivided metallic iron deposited on an inert carrier inamounts such thatthe weight of nickel is 20.8% and the weight of iron is 1.03% based onthe total weight of nickel, iron, and carrier was slurried with 200grams of a 50% aqueous solution of corn starch hydrolyzate containing63% dextrose and about 37% polysaccharides. The slurry was charged to anautoclave and heated for 30 minutes at C. and 2000 p.s.i.g. of hydrogen.The reaction product was then filtered, ion eX- changed and analyzed.The product contained, based on the weight of solids, 94.3% sorbitol.

Example 9 was repeated except that no nickel phosphate was added. Thefinal product contained 52.0% sorbitol based on the total weight ofsOlids in solution.

EXAMPLE 12 8.42 grams of a reduced catalyst consisting of finely dividedmetallic nickel and finely divided nickel phosphate supported on aporous carrier wherein the metallic nickel is 14.2% by weight and thenickel phosphate is 13.3% by weight, are slurried with 250 g. of 60%aqueous solution of sucrose under a nitrogen atmosphere. The resultingslurry has a pH of 6.3. The slurry is hydrogenated as described inExample 7 at 140 C. for 0.5 hour and at 160 C. for 0.5 hour, Whilemaintaining the hydrogen pressure at 2000 p.s.i.g. The reaction product,which has a pH of 4.9 is cooled and filtered. The filtrate, afterion-exchange and concentration to 70% solids,

analyzed on a dry basis 74.5% sorbitol and 24.3% man,

nitol.

EXAMPLE 13 612 grams of a 50% aqueous solution of glucose is slurriedwith 14.2 grams of a catalyst containing finely divided metallic nickeland finely divided nickel phosphate supported on kieselguhr wherein themetallic nickel content is 10.6% by weight and the nickel phosphatecontent is 22.4% by weight. The slurry is charged to an autoclave andheated for one hour in the presence of hydrogen at 140 C., whilemaintaining the hydrogen pressure at 1700-1900 p.s.i.g. The slurry isthen heated at 160 C. for one hour at 1800 p.s.i.g. of hydrogen. Thereaction product is then cooled, filtered, ion-exchanged, andconcentrated to 70% solids in solution. Based on the weight of solids insolution, the product contained 98.9% sorbitol.

EXAMPLE 14 Example 13 was repeated except that 13.9 grams of a catalystcontaining 14.6% by weight metallic nickel and 15.3% by weight nickelphosphate. The product contained 98.5% sorbitol based on the weight ofsolids in solution.

EXAMPLE 15 700 grams of a 50% aqueous solution of invert sugar isslurried with 8.1 grams of a catalyst containing finely divided metallicnickel and finely divided nickel phosphate supported on kieselguhrwherein the metallic nickel content is 13.7% by weight and the nickelphosphate content is 16.5% by weight. The slurry is pumped to anautoclave and heated for one hour at 160 C. in the presence of hydrogenat 1700 to 1850 p.s.i.g. The reaction product was filtered,ion-exchanged, and analyzed. The product contained, based on the weightof solids in solution, 74.3% sorbitol and 24.0% mannitol.

Although this invention has been described with reference to specificcarbohydrates and catalysts and to specific reaction conditions, it willbe appreciated that numerous other carbohydrates and catalysts may besubstituted for those described and that the particular reactionconditions employed may be modified, all within the spirit and scope ofthis invention as defined in the appended claims.

What is claimed is:

1. A catalyst which comprises finely divided metallic nickel and finelydivided nickel phosphate supported on an inert carrier wherein the totalnickel content is from 12 to 45% by weight, based on the total weight ofcatalyst, the phosphate (P0 content is from 0.6 to 23% by weight, basedon the total weight of catalyst, and the ratio of toal nickel tophosphorus is greater than 2.84.

2. A catalyst of claim 1 which contains iron in an amount up to 2.5% byweight of catalyst.

3. A catalyst of claim 2 wherein the weight percent of total nickel isfrom 15% to 30%, the weight percent of phosphate is from 1% to 14%, theWeight percent of iron is from 0.1% to 2%, and the ratio of total nickelto phosphorus is greater than 3.28.

4. A catalyst of claim 3 which contains up to 2% by weight of a promoterselected from the group consisting of chromium, cerium, and copper.

5. A catalyst of claim 3 wherein the inert carrier is selected from thegroup consisting of diatomaceous earth and activated carbon.

References Cited UNITED STATES PATENTS 1,963,999 6/ 1934 Larchar.2,650,941 9/1953 Koome et al. 3,144,415 8/1964 Silverman 2,524373,297,778 1/ 1967 Noddings et a1. 252-437 XR 3,341,609 9/1967 Kasehagen.

PATRICK P. GARVIN, Primary Examiner US. Cl. X.R. 260-635

